Method and device for dyeing a textile substrate

ABSTRACT

A method for dyeing a textile substrate, in particular for dyeing a textile substrate with reactive dyes, is described in which the textile substrate is brought in contact with a dyeing liquor containing at least one dye and after a predetermined dyeing time has elapsed, the dyed textile substrate is rinsed. The at least one dye which has not been fixed by the textile substrate and is present in the dyeing liquor is destroyed by a chemical and/or physical treatment to such an extent that the dyeing liquor is largely colourless hereafter, whereby the textile substrate being rinsed with the largely decolourised liquor. A device for carrying out the method comprises a vessel for receiving the textile substrate to be dyed and a circulation system for the dyeing liquor, where a reactor through which the dyeing liquor flows is assigned to the vessel and/or the circulation system and where inside the reactor the chemical and/or the physical treatment of the liquor to be decolourised is carried out.

The present invention relates to a method for dyeing a textile substratehaving the features of the preamble of claim 1 and a device for carryingout the method having the features of the preamble of claim 13.

In order to dye textile substrates, and in particular in order to dyethose textile substrates in which reactive dyes are used as the dye, itis known that the textile substrate is brought in contact with a dyeingliquor containing the dye or the dyes, where the dyed textile substrateis rinsed after a predetermined dyeing time has elapsed.

Depending on the respectively selected method and the equipmentavailable in each case, a distinction is made between a pad roll dyeing,a pad steam dyeing and an exhaustion dyeing, but all the methods have incommon that after the end of the actual dyeing process, rinsing isrequired to remove the non-fixed dye from the then dyed textilesubstrate.

This rinsing process required in any conventional dyeing method, whichis also designated as soaping process in the field of reactive dyeing,in principle constitutes a multiply repeated dilution process so that aconsiderable amount of water is required for this. For example, a liquorratio of 1:4 to 1:6 can be used for the exhaustion dyeing of a strand ofa textile web, i.e. between about 4 litre and 6 litre of water isrequired for one kilo of textile substrate to be dyed whereas overallliquor ratios which vary between 1:80 and 1:200 are required for theactual rinsing process, this overall liquor ratio being obtained fromthe fact that the rinsing process must be repeated many times, forexample, between four and eight times. In other words, when viewed as awhole, this rinsing process is on the one hand a very time-intensiveprocessing step and on the other hand, a very water-intensive processingstep.

It is the object of the invention to provide a method of the specifiedtype whereby the dyeing of a textile substrate, in particular, thedyeing of a textile substrate with reactive dyes, can be configuredparticularly economically.

This object is achieved according to the invention by a method havingthe characterising features of claim 1.

The inventive method for dyeing a textile substrate, in particular fordyeing a textile substrate with reactive dyes, provides that the textilesubstrate is brought in contact with a dyeing liquor containing at leastone dye and after a predetermined dyeing time has elapsed, during whichthe substrate is usually treated at an elevated temperature, the dyedtextile substrate is rinsed. Contrary to the known dyeing methodsdescribed initially however, in the inventive method, at the end of thedyeing the at least one dye which has not been fixed by the textilesubstrate and is still present in the dyeing liquor is destroyed by achemical and/or physical treatment to such an extent that the dyeingliquor is largely colourless hereafter so that the textile substrate isthereafter rinsed with the original dyeing liquor decolourised in thismanner.

Specifically, the application of the inventive method to an exhaustiondyeing means that in this case, at the end of the dyeing by theexhaustion dyeing, the dyeing liquor is not discharged into the channel,but the dyeing liquor is subjected to a chemical and/or physicaltreatment in such a manner that the original coloured dyeing liquor islargely decolourised as a result, and can be further used hereafter forrinsing the dyed textile substrate. This decolourisation process canthen be repeated, continuously or batchwise, sufficiently frequentlyuntil the non-fixed dye still present on the textile substrate isremoved without residue so that when viewed overall, in the mostfavourable case in the inventive method only one single liquor isrequired for the dyeing and also for the rinsing. As a result, by usingthe inventive method, it becomes possible to dye and rinse textilesubstrates and in particular, textile substrates to be dyed withreactive dyes with a liquor ratio of 1:4 to 1:6 so that compared to theprior art described initially, four to six litres of water are requiredfor dyeing and rinsing one kilo of textile substrate.

However, if the textile substrate is dyed by a pad roll dyeing or a padsteam dyeing, in the inventive method it is initially necessary to applythe dyeing liquor to the textile substrate depending on the degree ofsqueezing. About six hundred to nine hundred grams of dyeing liquor perkilo of textile substrate is required for this. After a predeterminedroll time (dwell time) or steaming time has elapsed, the textilesubstrate thus dyed is preferably rinsed in a liquor ratio of 1:4 to 1:6in which case, in the most favourable case in this variant of theinventive method, the first and only rinsing liquor then contains thedye which has not been fixed by the textile substrate and is present inthe rinsing liquor, which is then destroyed by a chemical and/orphysical treatment to such an extent that the rinsing liquor isthereafter largely colourless so that the textile substrate is thenrinsed again with the largely decolourised liquor. This destruction ofthe dye and renewed rinsing with the then decolourised rinsing liquorcan be repeated many times if necessary. consequently, this variant ofthe inventive method is also significantly more advantageous with regardto water consumption during rinsing compared to the conventional padroll dyeing or conventional pad steam dyeing, especially as liquorratios of 1:4.6 to 1:6.9 can be used in the inventive method.

In addition to the advantages described previously, the inventive methodalso has further advantages. It should first be noted that as a resultof the considerably reduced water requirement of the inventive methodcompared to a conventional method, the quantities of waste water areaccordingly also reduced considerably which is manifest in reducedenvironmental contamination and also in a considerably more favourablecost structure. Since in the most favourable case in the inventivemethod, only one rinsing bath is used, it is only necessary to heat thissingle rinsing bath once, whereas in the prior art where four to eightrinsing baths are used, these rinsing baths must be heated from roomtemperature to, for example, 80° C. again and again. In particular,since the inventive method dispenses with a liquor change during rinsing(soaping), the inventive method furthermore allows a considerable savingin time so that the throughput of substrate to be dyed per predeterminedunit time is increased appreciably by using the inventive method. Thisin turn leads to a considerable saving in staffing capacity which has apositive influence on the economic viability of the inventive method. Inaddition, it could also, surprisingly for the specialist world, beestablished that the textile substrate dyed and in particular rinsed bythe inventive method has a level of fastness, preferably a level offastness in relation to wet rubbing fastness, dry rubbing fastness,washing fastness as well as water fastness and perspiration fastnesswhich does not differ from textile substrates dyed by conventionalmethods.

In a first further embodiment of the inventive method, after apredetermined dyeing time has elapsed, the textile substrate is removedfrom the dyeing liquor and therefore from the apparatus used for thedyeing, and is transferred to another apparatus for rinsing. In thisother apparatus, the actual rinsing process is carried out in such amanner that the dye which adheres and is not fixed to the textilesubstrate, is initially transferred to the rinsing liquor where therinsing liquor laden with non-fixed dye is then subjected to a chemicaland/or a physical treatment so that after the treatment the rinsingliquor is largely colourless and, if necessary, can be used for furtherrinsing. This further embodiment of the inventive method has theadvantage that the rinsing process is carried out in the other apparatuswhich has a technically less complex structure compared to the actualdyeing apparatus so that such a working sequence can proceed in aparticularly cost-saving manner.

A particularly suitable further embodiment of the inventive methodprovides that the at least one dye not fixed by the textile substrateand present in the dyeing liquor or the rinsing liquor is destroyed by achemical treatment, where this chemical treatment is in particular anoxidative treatment.

In principle, all chemicals which allow the dye to be destroyed to suchan extent that colourless degradation products are the result, can beused for this chemical and preferably oxidative treatment, wherehydrogen peroxide or peracetic acid or sodium hypochlorite arepreferably used for this purpose.

In the inventive method however, it is particularly suitable if thepreviously described oxidative treatment of the dyeing liquor at the endof the actual dyeing comprises a treatment with ozone or is carried outexclusively by a treatment with ozone, where it has been establishedthat ozone destroys a plurality of different dyes and dye groups withinthe shortest time, i.e. within a few seconds to a few minutes, to suchan extent that colourless dye degradation products are obtained, havingno or only low substantivity to the textile substrate.

In principle, in the inventive method it is possible to treat the dyeingliquor at the end of the actual dyeing in a single bath to such anextent that the non-fixed dye which is still located in the dyeingliquor and on the surface of the textile substrate is decolourised bythe chemical and/or the physical treatment. However, it is particularlysuitable if the inventive method is varied so that the dyeing liquor isseparated from the dyed textile substrate and the chemical and/or thephysical treatment takes place thereafter so that accordingly, thedyeing liquor is preferably passed via a bypass to the actual dyeingapparatus and in this bypass, the dyes contained in the dyeing liquorare changed by a suitable chemical and/or a physical treatment to suchan extent that colourless degradation products of the dyes are formed bythis treatment. Accordingly, the dyeing liquor is then decolourised sothat it is then used as colourless rinsing liquor again to rinsenon-fixed dye from the dyed textile substrate. The dyed rinsing liquorthereby accumulating is then treated as described previously for theoriginal dyeing liquor so that after the chemical and/or the physicaltreatment, this can accordingly be used again as colourless rinsingliquor for further rinsing.

For clarification, it should be noted that the term “and/or” used in thepresent text means that the individual elements in the correspondinglisting can be seen as both additive or alternative, wherein with theadditive designation, at least two elements of the listing are thencombined with one another, whereas the term dye used in the singularnaturally should cover not only a single dye but also a mixture ofdifferent dyes.

Physical treatment in the scope of the present application should beunderstood as all treatments which are suitable for destroying the dyeto such an extent that colourless degradation products are formed as aresult. Accordingly, the liquor thus decolourised can be used for theactual rinsing process.

It is particularly suitable if this physical treatment takes place byirradiating the coloured liquor to be treated with UV light and/orapplying an electrochemical process using special diamond-coatedelectrodes, which are also designated as CVD electrodes in thespecialist terminology.

As has already been explained hereinbefore, in the inventive method, inthe favourable case, the dyed textile substrate is rinsed exclusivelywith the decolourised liquor at the end of the dyeing but in theinventive method, it cannot be excluded that at the end of the dyeing,which preferably comprises exhaustion dyeing, the dyeing liquor isdrained and replaced by a single rinsing liquor which is then subjectedto the chemical and/or physical treatment after contact with the dyedtextile substrate in order to destroy the non-fixed dyes containedtherein to such an extent that colourless degradation products and acolourless liquor are generated. This alternative of the inventivemethod can be used whenever the residual dye concentration in the dyeingliquor is so high that the expenditure for decolourisation by means ofthe chemical and/or physical treatment is too high and thus a singlechange of liquor is more favourable for economic considerations.

However, it is particularly suitable and economically favourable if in amodification of the inventive method in which the textile substrate isrinsed with the decolourised dyeing liquor in a first step, in a secondstep the rinsing liquor laden with non-fixed dye is separatedthereafter, in a third step the non-fixed dye located in the rinsingliquor is destroyed to such an extent by the chemical and/or physicaltreatment that the rinsing liquor is largely colourless and that in afourth step the textile substrate is rinsed with the largely colourlessrinsing liquor.

Depending on which textile substrate is dyed with which dyes and towhich colour intensity by the inventive method, an alternative of theinventive method provides that the first to the fourth step is repeatedmultiple times, in particular twice to fifteen times.

As has already been shown to be advantageous previously, an embodimentof the inventive method provides that treatment with ozone is carriedout as the chemical treatment of the dyeing liquor and/or as thechemical treatment of the rinsing liquor, the treatment with ozonehaving the decisive advantage that the ozone decomposes again within theshortest time, i.e. a few seconds. In order to reduce the control andregulating expenditure as well as the safety expenditure in theinventive method, the treatment with ozone can be carried out in areactor allocated to the respective dyeing apparatus or the rinsingdevice, where the dyeing liquor to be decolourised and/or the rinsingliquor to be decolourised flows continuously through this reactor. Inother words, in this embodiment of the inventive method, the dyedtextile substrate is separated from the ozone treatment stage of thedyeing liquor and/or the ozone treatment stage of the rinsing liquor sothat it is accordingly ensured that the ozone does not acts on thosedyes which are already fixed to the textile substrate.

In order to ensure that in the previously described particularlyadvantageous further embodiment of the inventive method, no decolourisedliquor (dyeing liquor or rinsing liquor) still laden with residual ozonecomes in contact with the dyed textile substrate, it has been shown tobe particularly advantageous if a redox potential measurement, an ozonemeasurement and/or a pH-value measurement of the ozone-treated liquor ismade at the outlet of the reactor. If the corresponding measured valuesshould then indicate the presence of residual ozone in thecorrespondingly treated liquor, this residual ozone can be removed fromthe liquor by a short-term increase in temperature which can be achievedin terms of apparatus by providing another bypass here which is thentriggered with such a residual-ozone containing liquor via correspondingvalve settings.

As another possibility or in addition to the previously discussedvariant, the inventive method is operated in such a manner that thequantity of ozone fed into the reactor is controlled depending on themeasured redox potential, the measured ozone concentration and/or themeasured pH value so that the quantity of ozone fed into the reactor isreduced accordingly when residual ozone is determined in thedecolourised liquor.

In principle, the inventive method can be used in any dyeing method, inparticular in the pad roll dyeing or pad steam dyeing described brieflyat the beginning. In this case, after application and fixing of the dye,the textile substrate thus dyed is usually rinsed on a suitableinstallation, either continuously or discontinuously, and in thisvariant of the inventive method, the rinsing liquor is then subjected tothe previously described chemical and/or physical treatment to destroythe dye contained in the rinsing liquor to such an extent that therinsing liquor is largely colourless. The inventive method can just aswell be applied to dyeing which is carried out on a jigger in the normaland high-temperature range. However, it is particularly appropriate ifthe inventive method is used in exhaustion dyeing methods since in thiscase, as described initially, a dyeing liquor is available which can beaccordingly treated physically and/or chemically for decolouration.Likewise, there are no restrictions as to the form of preparing thetextile substrate prior to dyeing (make-up of the textile substrate) towhich the inventive method is applied. The inventive method can be alsobe used for yarn dyeing, either cross-wound bobbin or strand dyeing, butit is also suitable if the textile substrate as a textile fabric andpreferably as a continuous web strand is dyed by the inventive methodsince the savings of water discussed previously are shown particularlyclearly here.

The present invention further relates to a device for carrying out theinventive method as described previously, whereby the inventive methodcan be carried out particularly economically.

The inventive device for carrying out the inventive method as describedpreviously in particular comprises a vessel (housing) for receiving thetextile substrate to be dyed and a circulation system for the dyeingliquor, wherein a reactor through which the dyeing liquor flows isassigned to the vessel and/or the circulation system. Inside the reactorthe chemical and/or physical treatment of the liquor to be decolourised(dyeing liquor at the end of the dyeing process and/or rinsing liquor)is carried out.

The previously described inventive device has all the advantages asthese have already been before described for the inventive method. Inparticular, the inventive device allows a rational use of a textilesubstrate to be dyed by an exhaustion dyeing method, where disturbancesand in particular undesirable damage of the dyed textile substrate isavoided by carrying out the actual physical and/or chemical treatmentfor discolouring the liquor in a separate reactor.

Likewise, it is possible to have an embodiment of the inventive devicein which the vessel for receiving the textile substrate to be dyed formsthe reactor for carrying out the chemical and/or physical treatment. Inother words, in this embodiment the actual reactor is formed by thedyeing vessel itself or by a separately arranged other apparatusdescribed previously in the inventive method, to which the textilesubstrate which has been dyed but not yet been rinsed is transferred forrinsing, so that the chemical and/or physical treatment is carried outfollowing the dyeing in the dyeing vessel itself or in the otherapparatus.

A particularly suitable and space-saving embodiment of the inventivedevice proposes that in this case, a first piping system for the dyeingliquor is located in the bottom region of the vessel in which the actualdyeing and rinsing takes place and this connects the reactor via a firstvalve and via a liquor pump to the bottom region of the vessel, thereactor being connected by means of a second piping system and a secondvalve to the vessel for supplying the largely colourless dyeing liquoror rinsing liquor after the treatment. Generally speaking, the bottomregion of the vessel is connected via a valve and a liquor pump to thereactor and the reactor itself is again connected via a valve to thevessel so that the actual treatment step for the chemical and/orphysical decolourising of the liquor takes place in this reactor whichis connected as a bypass. At the end of the actual dyeing, therespective dyeing liquor is therefore supplied to the reactor with theaid of the liquor pump and a suitably opened first valve, the chemicaland/or physical treatment of the liquor for destroying of the dye andtherefore for decolourising the same is carried out there so that thethus decolourised liquor is then fed back to the vessel again via thesecond valve to initiate the actual rinsing process.

In order to ensure the required constant temperature in the previouslydescribed variant of the inventive device and in order furthermore,should this be necessary, to remove undesirable residues of ozone and/orother oxidation agents from the decolourised liquor flowing back to thevessel, a further embodiment of the inventive device provides that aheat exchanger is assigned to the second piping system.

Moreover, in another embodiment of the inventive device at least onesensor for detecting the redox potential, the ozone concentration and/orthe pH value is assigned to the second piping system so that undesirableresidues of oxidation agents and in particular, undesirable residues ofozone are detected by means of the at least one sense at a time before aliquor laden with such residual oxidation agents or residual ozone comesin contact with the dyed textile substrate, which can possibly lead todefects. In order to eliminate such an error source, the at least onesensor is located before the second valve when viewed in the directionof flow of the liquor, this second valve preferably being configured insuch a manner that when an undesirable residual concentration ofoxidation agents and in particular of ozone is detected the respectiveliquor stream is fed via the second valve, for example, to a heatexchanger, to expel these undesirable residues, and only then is theresidue-free liquor fed to the vessel.

In the embodiments of the inventive device in which the non-fixed dyefrom the dyeing liquor or from the rinsing liquor is destroyed by ozonetreatment to such an extent that colourless components are formedtherefrom, it is possible to assign a device for generating ozone to thereactor, such devices being known per se in the prior art. Naturally,however it is also possible to act upon the reactor with ozone byproviding suitable ozone storage tanks here. This variant isparticularly suitable if the dyeing liquor still has a highconcentration of non-fixed dye at the end of the actual dyeing processso that an increased amount of ozone is therefore used in the reactor inorder to destroy this residual non-fixed dye by the ozone treatment tosuch an extent that colourless components are produced from this.

For safety reasons, it is recommended that in a further embodiment ofthe inventive device a third piping system is allocated to the reactor,which piping system connects the air space in the reactor to an exhaustair fan via a residual ozone annihilator and a third valve. In thiscase, it is furthermore particularly advantageous if a sensor fordetecting the ozone concentration is provided in the exhaust air so thata corresponding audible or visual signal is optionally generated beforeexhaust air enriched with ozone can enter into the atmosphere.

In order that a sufficient quantity of ozone required for treatment ofthe dyeing liquor or the rinsing liquor is always available, anotherembodiment of the inventive device provides that the ozone generator isconnected to a source for oxygen-enriched air so that the actual ozonegeneration accordingly takes place particularly rapidly directly beforeits use.

As has already been stated hereinbefore, the inventive device is used inparticular for those dyeing methods using the exhaustion process wherethe inventive device is then accordingly adapted to the make-up of thegoods to be dyed.

Thus, the first possibility provides that the vessel for receiving thetextile substrate to be dyed comprises a storage system assigned to thebottom region, and a deflecting device for the web strand is providedabove the vessel. Furthermore, the deflecting device for the web strandcomprises a driven mandrel and/or a nozzle channel so that the webstrand is therefore transported and folded continuously during thedyeing and also during the rinsing.

A second possibility which is particularly used for dyeing a web in thebroad and bound state envisages providing a cylindrical vessel which isequipped with a dye beam (perforated beam) for receiving a web roll.

The third possibility further develops the inventive device in that thevessel has at least one holder for receiving at least one bobbin, inparticular at least one cross-wound bobbin so that this variant of theinventive device is accordingly adapted for the bobbin dyeing.

In order to prevent undesirable disturbance of the process sequence inthe inventive method or in the treatment of the textile substrate to bedyed in the inventive device, a liquor circulating pump, a heatexchanger, a colour trough (dye feed tank) and/or a lint catcher (fibrewaste trap) is assigned to the circulation system through which thedyeing liquor flows during the actual dyeing process and thedecolourised dyeing liquor at the end of the dyeing process or thedecolourised rinsing liquor.

Advantageous further developments of the inventive method and theinventive device are specified in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic of the device of the invention.

The inventive method and the inventive device will be explained indetail hereinafter with reference to an exemplary embodiment of theinventive device. In this case, the single figure shows a schematicdiagram of the inventive device.

The embodiment of the device designated overall as 11, shown in thesingle figure, initially comprising a conventional dyeing installation10 provided with a vessel 12 for receiving the web strand 13 to be dyed.During the dyeing and rinsing the web strand 13 is transportedcontinuously through the vessel 12, a driven mandrel 14 being used fortransporting this web strand 13 in the embodiment shown.

A liquor circulation system 16 is assigned to the bottom region 15 ofthe vessel 12, where the respective treatment liquor is withdrawn fromthe vessel 12 via this liquor circulation system 16 by means of a liquorcirculating pump 17 and a heat exchanger 18 and is fed into the vessel12 again after heating the liquor. During the treatment, the web strand13 is transported by means of the mandrel 14 at a predetermined speed inthe direction of the arrow 19 a, the transport speed usually varyingbetween 200 m/min and 800 m/min. Furthermore, a lint catcher not shownand a colour trough are assigned to the liquor circulation system 16.

A reactor 6 is provided in a bypass to the dyeing installation 10, inwhich the actual chemical and/or physical treatment of the dyeing liquoror the rinsing liquor takes place, where in the embodiment shown, thenon-fixed dye is subjected to a chemical treatment with ozone to destroythe dye to such an extent that colourless components are generated. Thereactor 6 is connected via a line 3 to an ozone generator 2, whereoxygen-enriched air is fed via the line 1 in the ozone generator. Inaddition, on the input side the reactor 6 is connected via a firstpiping system 19 to the bottom region 15 of the vessel 12, where a valve20, a liquor pump 4 and a heat exchanger 5 are provided when viewed inthe direction of flow of the liquor from the vessel 12 to the reactor 6.

In addition, the reactor 6 is connected to the bottom region 15 of thevessel 12 by means of a second piping system 21 via a sensor 7 and asecond valve 22, again viewed in the direction of flow of the liquor.

Finally, a third piping system 23 opens from the reactor 6 to an exhaustair fan 9 which connects the air space provided in the reactor 6 via aresidual ozone annihilator 8 to the exhaust air fan 9, where the exhaustair fan 9 is open to the atmosphere.

The device shown in the figure operates as follows:

Firstly, the dyeing installation 10 is provided with the textile webstrand 13, where for this purpose the web strand 13 is made up as acontinuous web strand and is positioned inside the vessel 12. The vesselis then filled with dyeing liquor in its lower region, where the liquoris continuously pumped around by means of the liquor circulation system16 during the actual dyeing, and the web strand 13 is continuouslytransported. Such a dyeing installation 10 and its operating mode havebeen prior art for a long time before.

After the dyeing has now been completed in the dyeing installation 10,the dyeing liquor located in the vessel 12 is pumped continuously to thereactor 6 by opening the valve 20 and with the aid of the liquor pump 4and via the heat exchanger 5 via the first piping system 19, whereby theliquor in the reactor still containing residual dye which has not beenexhausted and fixed is treated with ozone in the reactor 6. In thiscase, the ozone is continuously created in the ozone generator 2 fromthe oxygen-enriched air supplied via the line 1 and is added to thereactor in a predetermined quantity by means of the line 3. The quantityof ozone is controlled so that on the one hand, the liquor leaving thereactor 6 is colourless and on the other hand, no more residual ozone isdisplayed on the sensor provided in the second piping system 21.However, should residual ozone still be detected here, the valves 20 and22 provided in the piping systems 19 and 21 which are open during thetreatment, are automatically closed. At the same time, the pump 4 isswitched off so that the process in the reactor is interruptedinstantaneously.

The liquor thus decolourised by means of the ozone treatment passes viathe second piping system 21 and the opened valve 22 into the bottomregion 15 of the vessel and rinses the dyed web strand 13 which iscontinuously transported at a predetermined speed in the direction ofthe arrow 19 a.

After a predetermined time has elapsed which depends on the substrate tobe dyed, the selected dye, the colour intensity, the liquor ratio and/orthe loading of the vessel 12 as well as the transport speed, the rinsingprocess is now ended, and the residual ozone remaining in the system, inparticular the residual ozone located in the reactor, is destroyed bymeans of the residual ozone annihilator 8 so that ozone-free exhaust aircan be removed from the system via the exhaust gas fan 9.

The vessel 12 can then be ventilated and a dyed and perfectly rinsed webstrand can be removed from the vessel 12 so that the previouslydescribed dyeing and rinsing process can be carried out with an overallliquor ratio of 1:4 to 1:6 in total.

1. A method for dyeing a textile substrate, in particular for dyeing atextile substrate with reactive dyes, in which the textile substrate isbrought in contact with a dyeing liquor containing at least one dye andafter a predetermined dyeing time has elapsed, the dyed textilesubstrate is rinsed, wherein the at least one dye which has not beenfixed by the textile substrate and is present in the dyeing liquor isdestroyed by a chemical and/or physical treatment to such an extent thatthe dyeing liquor is largely colourless hereafter and that the textilesubstrate is rinsed with the largely decolourised liquor.
 2. The methodaccording to claim 1, wherein after a predetermined dyeing time haselapsed, the textile substrate is removed from the dyeing liquor and istransferred to an apparatus for rinsing, wherein the rinsing liquorladen with non-fixed dye is subjected to chemical and/or physicaltreatment.
 3. The method according to claim 1, wherein the at least onedye not fixed by the textile substrate and present in the dyeing liquoror the rinsing liquor is destroyed by a chemical treatment.
 4. Themethod according to claim 1, wherein an oxidative treatment is carriedout as the chemical treatment.
 5. The method according to claim 4,wherein a treatment with ozone is carried out as the oxidativetreatment.
 6. The method according to claim 1, wherein the dyeing liquoris separated from the dyed textile substrate and the chemical and/orphysical treatment takes place thereafter.
 7. The method according toclaim 6, wherein the textile substrate is rinsed exclusively with thedecolourised liquor.
 8. The method according to claim 7, wherein thetextile substrate is rinsed with the decolourised dyeing liquor in afirst step, that in a second step the rinsing liquor laden withnon-fixed dye is separated thereafter, that in a third step thenon-fixed dye located in the rinsing liquor is destroyed to such anextent that the rinsing liquor is largely colourless and that in afourth step the textile substrate is rinsed with the largely colourlessrinsing liquor.
 9. The method according to claim 8, wherein the first tothe fourth step is repeated multiple times, in particular twice tofifteen times.
 10. The method according to claim 1, wherein treatmentwith ozone is carried out as the chemical treatment of the dyeing liquorand/or the rinsing liquor and that the treatment with ozone is carriedout in a reactor allocated to the respective dyeing apparatus, throughwhich the dyeing liquor and/or the rinsing liquor flows continuously.11. The method according to claim 10, wherein a redox potentialmeasurement, an ozone measurement and/or a pH measurement of theozone-treated liquor is made at the outlet of the reactor.
 12. Themethod according to claim 11, wherein the quantity of ozone fed into thereactor is controlled depending on the measured redox potential, themeasured ozone concentration and/or the measured pH value.
 13. Themethod according to claim 1, wherein a fabric is dyed as the textilesubstrate.
 14. A device for carrying out the method according to claim1, comprising a vessel for receiving the textile substrate to be dyedand a circulation system for the dyeing liquor, wherein a reactor (6)through which the dyeing liquor flows is assigned to the vessel (12)and/or to the circulation system (16) and that in the reactor (6) thechemical and/or physical treatment of the liquor to be decolourised iscarried out.
 15. The device according to claim 14, wherein the vessel(12) for receiving the textile substrate to be dyed forms the reactorfor carrying out the chemical and/or physical treatment.
 16. The deviceaccording to claim 14, wherein a first piping system (19) for the dyeingliquor is located on the bottom region (15) of the vessel (12), whichconnects the reactor (6) via a first valve (20) and via a liquor pump(4) to the bottom region (15) of the vessel (12) and that the reactor(6) is connected by means of a second piping system (21) and a secondvalve (22) to the vessel (12) for supplying the largely colourlessdyeing liquor after the treatment.
 17. The device according to claim 16,wherein a heat exchanger (18) is assigned to the second piping system(21).
 18. The device according to claim 16, wherein at least one sensor(7) for detecting the redox potential, the ozone concentration and/orthe pH-value is assigned to the second piping system (21), wherein theat least one sensor (7) is located before the second valve (22) whenviewed in the direction of flow of the liquor.
 19. The device accordingto claim 14, wherein a device (1, 2, 3) for generating ozone is assignedto the reactor (6).
 20. The device according to claim 19, wherein athird piping system (23) is allocated to the reactor (6), which pipingsystem connects the air space in the reactor (6) to an exhaust air fan(9) via a residual ozone annihilator (8) and a third valve.
 21. Thedevice according to claim 19, wherein the ozone generator (1, 2, 3) isconnected to a source for oxygen-enriched air.
 22. The device accordingto claim 14, wherein the vessel (12) for receiving the textile substrate(13) to be dyed comprises a storage system assigned to the bottom region(15), that a deflecting device (14) for the web strand (13) is providedabove the vessel (12), wherein the deflecting device (14) for the webstrand comprises a driven mandrel and/or a nozzle channel.
 23. Thedevice according to claim 14, wherein the vessel has a dye beam forreceiving a web strand.
 24. The device according to claim 14, whereinthe vessel has at least one holder for receiving at least one bobbin, inparticular at least one cross-wound bobbin.
 25. The device according toclaim 14, wherein the liquor circulation system (16) is provided with aliquor circulating pump (17), a heat exchanger (18), a lint catcherand/or a colour trough.